blakefogt's 1987 4Runner Build-Up Thread
08-16-2011, 08:39 PM
#121
I would not think the IACV has anything to do with that.... If anything, it just get's out of the way when it's caput(Meaning; It will just no longer "IDLE UP".... rather, it will just start at 750rpm and stay there).
The IACV basically bypasses the preset throttle stop plate when cold. It does this by staying open between the 2 large vacuum hoses attached to itself, front and back. That arm inside is controlled by 'coolant temp'. As the coolant is heating UP to 96*F(somewhere around there)... it slowly closes that arm/closing the gate that's allowing more "AIR" to be pulled in through to the plenum(the front big hose) through the IACV and then into the plenum, directly(via the REAR big hose). I wound up with a new one only because mine failed all the advanced tests... And basically, the 'bi-metallic arm' controlled by coolant temp had worn out(There is also a small spring inside that pulls on that gate... As there is also a small diameter hole in the gate, even once it's closed). I have some pics of this stuff in my troubleshooting thread or build thread.... SOMEWHERE, being the key word! lol.
That condition you're experiencing when cold could be many things, but doubtfully the IACV... Could be IGN related, EFI related or even Sensor related/via either the EFI loop. Even the AFM can malfunction related to Ambient Temp or other readings it's getting. Also, ...remember the AFM gate/flap, as it opens, activates the fuel pump when the key is turned over(maybe even in STA position).
How's the fuel filter?
Gotta start doing a decent Process Of Elimination, Blake. Bust out the Troubleshooting section of the FSM, homie.
The IACV basically bypasses the preset throttle stop plate when cold. It does this by staying open between the 2 large vacuum hoses attached to itself, front and back. That arm inside is controlled by 'coolant temp'. As the coolant is heating UP to 96*F(somewhere around there)... it slowly closes that arm/closing the gate that's allowing more "AIR" to be pulled in through to the plenum(the front big hose) through the IACV and then into the plenum, directly(via the REAR big hose). I wound up with a new one only because mine failed all the advanced tests... And basically, the 'bi-metallic arm' controlled by coolant temp had worn out(There is also a small spring inside that pulls on that gate... As there is also a small diameter hole in the gate, even once it's closed). I have some pics of this stuff in my troubleshooting thread or build thread.... SOMEWHERE, being the key word! lol.
That condition you're experiencing when cold could be many things, but doubtfully the IACV... Could be IGN related, EFI related or even Sensor related/via either the EFI loop. Even the AFM can malfunction related to Ambient Temp or other readings it's getting. Also, ...remember the AFM gate/flap, as it opens, activates the fuel pump when the key is turned over(maybe even in STA position).
How's the fuel filter?
Gotta start doing a decent Process Of Elimination, Blake. Bust out the Troubleshooting section of the FSM, homie.
Ign I've replaced cap/rotor/wires/plugs all within the last 6 or 7k
Possibly EFI. I don't think it's the AFM in relation to ambient temperature, when i say cold I mean engine cold not ambient cold. um.... fuel filter.. again I would think a clogged filter would be an issue more than just initial start up with a cold engine
thanks for all the thinkin materials! I wish I wasn't sick right now, or I'd be out there tinkering. OH I have a friend who wants to sell his bug for 750 bucks.. its a 66 says hes driven it to new mexico and back just needs paint.. So Now I'm torn between a cheap ol bug, and a full exhaust for my truck... hmmmm I guess it depends on the quality of the car... if its good I know i can flip it in a month's time.
08-16-2011, 09:44 PM
#122
Only mentioning the Ambient Temp portion of the AFM to relate how ANYTHING can cause issues... And as an example; If that portion of the AFM is malfunctioning.... the trucks fuel mixture is adjusted for 120*F weather(just example) when it's really 69*F outside... Ya know?
Fuel filter, ....DON'T THINK, lol. If it's old, replace it, OEM. (No, not likely the 'source' of cold start issues.... but when they start to fail/clog, they don't ALWAYS do things you would expect... They sometimes sputter, wont stay running,...then run all day, then wont run again. Eventually of course, ...... it will barely run, ever.
Just for the hell of it... bypass the FPR-VSV... Plug the line to the FPR directly into the plenum where the VSV is 'getting' it's vacuum. I'm NOT saying it's even likely, but it's free and takes 30 seconds. (4crawler has it on his cheap tricks).
Far as the IGN components you've replaced.... That's about half of it. Secondary Coil, Coil, Ignitor, Dizzy, Air Gap(ALSO doubtful on most of them.. but that's why it's a P.O.E..... cuz you eliminate that group and move forward)>>> ask me how I now know to be thorough with my P.O.E.??? hahahaha.
You gotta start with 'FUEL'. Of course, start with the 'FUEL' WHEN it's doing it, lol... But WIMean is, ... verify you have fuel pump engagement through the COR, AFM, do the Fuel Pump Bypass check with the diag. port.... things like that.
Sorry you're sick, man... BITES TO BE SICK, I HATE IT! .....HEY, ...BACK UP, .....YA MIGHT GIVE IT TO MEEEEEE~! HAHAHA.
Get well, soon, Blake!
Fuel filter, ....DON'T THINK, lol. If it's old, replace it, OEM. (No, not likely the 'source' of cold start issues.... but when they start to fail/clog, they don't ALWAYS do things you would expect... They sometimes sputter, wont stay running,...then run all day, then wont run again. Eventually of course, ...... it will barely run, ever.
Just for the hell of it... bypass the FPR-VSV... Plug the line to the FPR directly into the plenum where the VSV is 'getting' it's vacuum. I'm NOT saying it's even likely, but it's free and takes 30 seconds. (4crawler has it on his cheap tricks).
Far as the IGN components you've replaced.... That's about half of it. Secondary Coil, Coil, Ignitor, Dizzy, Air Gap(ALSO doubtful on most of them.. but that's why it's a P.O.E..... cuz you eliminate that group and move forward)>>> ask me how I now know to be thorough with my P.O.E.??? hahahaha.
You gotta start with 'FUEL'. Of course, start with the 'FUEL' WHEN it's doing it, lol... But WIMean is, ... verify you have fuel pump engagement through the COR, AFM, do the Fuel Pump Bypass check with the diag. port.... things like that.
Sorry you're sick, man... BITES TO BE SICK, I HATE IT! .....HEY, ...BACK UP, .....YA MIGHT GIVE IT TO MEEEEEE~! HAHAHA.
Get well, soon, Blake!
Last edited by ChefYota4x4; 08-16-2011 at 09:45 PM.
08-18-2011, 01:51 PM
#123
Well, I'm feeling better and I drive to work today.. and the ol misfire has decided it needs more attention. blatent at idle... and can be heard felt in nuetral up to about 3k
Driving down the road, I get similar results.. I haven't done a valve adjust since I got the truck... about 15k miles ago so I'm going to start there. All the plugs look typical of 7,000 mile plugs... ordered the gasket, halfmoons and grommets from toyota.. Now I'm just hoping its an exhaust valve adjustment that's allowing air/fuel straight through and popping in the header/exhaust. *finger's crossed* I'm still pretty convinced the IAC-V is acting up due to not enough initial throttle.. couple of ex toyota techs, current lexus techs agree.. so maybe I'm just no good at describing symptoms
Driving down the road, I get similar results.. I haven't done a valve adjust since I got the truck... about 15k miles ago so I'm going to start there. All the plugs look typical of 7,000 mile plugs... ordered the gasket, halfmoons and grommets from toyota.. Now I'm just hoping its an exhaust valve adjustment that's allowing air/fuel straight through and popping in the header/exhaust. *finger's crossed* I'm still pretty convinced the IAC-V is acting up due to not enough initial throttle.. couple of ex toyota techs, current lexus techs agree.. so maybe I'm just no good at describing symptoms
08-18-2011, 04:39 PM
#124
well toyotas are known to have bad iacv. its not often i see one at work tho. maybe try performing a EFI service.
when the truck does idle. does it jump up and down a little bit? look at 2 4 and 6 ignition wire and make sure its not arcing on the egr. i had wires not routed wrong once and the egr burned the ignition wire causing a misfire
when the truck does idle. does it jump up and down a little bit? look at 2 4 and 6 ignition wire and make sure its not arcing on the egr. i had wires not routed wrong once and the egr burned the ignition wire causing a misfire
08-18-2011, 05:24 PM
#125
Glad you're feeling better, man
By all means, let the Toyota Tech's show you what they mean/diagnose that for ya! FO SHO!
Only thing, .... I've had 3 bad IACV's in a row(from the yard and the orig. on my last truck), ..... finally bought a new one at the Dealer(20% off, 90$)... Well, it solved my 'idle up problem' in the morning(IOW... I FINALLY idled up, when cold, after replacing it)... But as I dug a lil deeper into it's purpose/effect on other things... I just couldn't personally find ANYTHING that it might cause in regards to my 'miss', 'erratic idle', bogging down/idling up on it's own stuff.... and it did nothing to solve/lessen those issues(Issues that all occurred after the rig had fully warmed up, or in some cases, just as it went into closed loop).
So, just to get it all clear(that's me, not you, ...i'm a bit overwhelmed at the moment! lol)....
1. You have a sputter and die issue( just lately, on occasion?)
2. ?
3. ?
Could you just lay out all it's doing, precisely when it does it, differences on freeway, etc.? My issues with sputtering and dying, 3 times, were a bad 02, a totally bad CTSensor and a wacked out TPS... Lots of things it could be, ...but man, I just wish our OBD1's were OBD2, at least, don't you? hahahah.
Out of curiosity.... when you take off from a stop, ....does it act boggish, then BAT OUT OF HELL all the sudden, only after you reach like 2200-2500rpm?
By all means, let the Toyota Tech's show you what they mean/diagnose that for ya! FO SHO!
Only thing, .... I've had 3 bad IACV's in a row(from the yard and the orig. on my last truck), ..... finally bought a new one at the Dealer(20% off, 90$)... Well, it solved my 'idle up problem' in the morning(IOW... I FINALLY idled up, when cold, after replacing it)... But as I dug a lil deeper into it's purpose/effect on other things... I just couldn't personally find ANYTHING that it might cause in regards to my 'miss', 'erratic idle', bogging down/idling up on it's own stuff.... and it did nothing to solve/lessen those issues(Issues that all occurred after the rig had fully warmed up, or in some cases, just as it went into closed loop).
So, just to get it all clear(that's me, not you, ...i'm a bit overwhelmed at the moment! lol)....
1. You have a sputter and die issue( just lately, on occasion?)
2. ?
3. ?
Could you just lay out all it's doing, precisely when it does it, differences on freeway, etc.? My issues with sputtering and dying, 3 times, were a bad 02, a totally bad CTSensor and a wacked out TPS... Lots of things it could be, ...but man, I just wish our OBD1's were OBD2, at least, don't you? hahahah.
Out of curiosity.... when you take off from a stop, ....does it act boggish, then BAT OUT OF HELL all the sudden, only after you reach like 2200-2500rpm?
08-18-2011, 09:28 PM
#126
1. the start up issue is start die instant no really sputter hence my iacv worries
2.once i get her idling under her own power, about once every... 3 seconds (just a guess) i get a misfire. rev to 2-3 k it will be a consistant.. maybe two pops a second. take of driving and its still doing the same thing.
my current theories
1. faulty iac-v
2. tight valve (according to my dad and family friend both yota techs in the late 80s early 90s) these engines got regular valve adjustments to compensate for them tightening themselves over time. It would make sense that the air/fuel is just passing right through and exploding whenever it feels hot enough.
but yea doing my research lately, basically just about anything could cause a misfire, and with 25 year old electronics... these sensors can easily develope dead spots and confuse injectors.
my valve cover gasket, half moons, and grommets should be in tomorrow. after work the plan is to replace my bugs fuel pump and do the valve job
onto a bit brighter news. The current plan is, new exhaust from the downey header back (high flow cat) to... unsure of muffler as of yet. Flowmaster seems like a fine brand... sounds sick on my mom's 5.4L f150
then! save up for the blazeland kit we all drool over
2.once i get her idling under her own power, about once every... 3 seconds (just a guess) i get a misfire. rev to 2-3 k it will be a consistant.. maybe two pops a second. take of driving and its still doing the same thing.
my current theories
1. faulty iac-v
2. tight valve (according to my dad and family friend both yota techs in the late 80s early 90s) these engines got regular valve adjustments to compensate for them tightening themselves over time. It would make sense that the air/fuel is just passing right through and exploding whenever it feels hot enough.
but yea doing my research lately, basically just about anything could cause a misfire, and with 25 year old electronics... these sensors can easily develope dead spots and confuse injectors.
my valve cover gasket, half moons, and grommets should be in tomorrow. after work the plan is to replace my bugs fuel pump and do the valve job
onto a bit brighter news. The current plan is, new exhaust from the downey header back (high flow cat) to... unsure of muffler as of yet. Flowmaster seems like a fine brand... sounds sick on my mom's 5.4L f150
then! save up for the blazeland kit we all drool over
Last edited by blakefogt; 08-18-2011 at 09:34 PM.
08-18-2011, 10:14 PM
#127
Going through some diagnosis with a buddy, JasonTN, .... Just posted some FSM pages for him to read through... Posted some of the "Cranks fine/Wont start" stuff... along with the "Rich-condition, After-Fire" etc. as well. It's in the FSM starting like chapter FI- Pg. 12 or so.
Most of what it lists is CSInjector/Time switch as well, Coolant Temp Sensor, Short between ECU and injectors, amongst other things.
Like I said, I can only tell you what I've experienced. I'm no Toyota Tech, but I've learned a lot in the last couple years... and I've actually dealt with 2 totally non-working IACV's, ....they never stopped it from starting. I just would hate for you to replace that, first, in an effort to find your 'non-start' issues....
I also had a misfire, miss, REALLY bad mileage, ...all due to a 'Bad Cam', 'Poorly Bored Block', 'Poorly Ground Crank', etc. Many sensors are new,....and one of them giving me major problems was the Coolant Temp Sensor, my fairly bad leaking CSI and originally, my C.O.R. was really corroded, causing "Drive around for a while, fine, ....then turn it off, go to start it, NOTHING" issues, lol. Eventually, it just completely gave up, ....replaced it, 'voila', solved. The coolant Temp sensor was causing weird idling... Sometimes too high and would seem to stick there and other times it would just not want to 'get up and go'.
Hope you and your buddies can figure it out, soon!
BTW, ... I have an extra IACV, ...it doesn't idle up very well, but it was installed and my truck started every time. Maybe you could try it out? Might save ya 100$+ just for testing purposes. (PS> It's from an 87, mine, lol.) Only reason I changed it is because, going into a SECOND FULL REBUILD!>>> I wanted it to idle up when cold, then I can take off when it's warm enough, as the idle drops back down to 750rpm. I think it still idled up to like 850 or so. Up to you, let me know.
Most of what it lists is CSInjector/Time switch as well, Coolant Temp Sensor, Short between ECU and injectors, amongst other things.
Like I said, I can only tell you what I've experienced. I'm no Toyota Tech, but I've learned a lot in the last couple years... and I've actually dealt with 2 totally non-working IACV's, ....they never stopped it from starting. I just would hate for you to replace that, first, in an effort to find your 'non-start' issues....
I also had a misfire, miss, REALLY bad mileage, ...all due to a 'Bad Cam', 'Poorly Bored Block', 'Poorly Ground Crank', etc. Many sensors are new,....and one of them giving me major problems was the Coolant Temp Sensor, my fairly bad leaking CSI and originally, my C.O.R. was really corroded, causing "Drive around for a while, fine, ....then turn it off, go to start it, NOTHING" issues, lol. Eventually, it just completely gave up, ....replaced it, 'voila', solved. The coolant Temp sensor was causing weird idling... Sometimes too high and would seem to stick there and other times it would just not want to 'get up and go'.
Hope you and your buddies can figure it out, soon!
BTW, ... I have an extra IACV, ...it doesn't idle up very well, but it was installed and my truck started every time. Maybe you could try it out? Might save ya 100$+ just for testing purposes. (PS> It's from an 87, mine, lol.) Only reason I changed it is because, going into a SECOND FULL REBUILD!>>> I wanted it to idle up when cold, then I can take off when it's warm enough, as the idle drops back down to 750rpm. I think it still idled up to like 850 or so. Up to you, let me know.
08-20-2011, 08:44 AM
#129
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hey blake, sorry about the miss fire problem your having. and thank you for willing to help me with the multi meter i appreciate it. i wish i could help but im still learning myself
08-22-2011, 12:03 PM
#130
no worries guys, all my valves were excessively tight so I adjusted them (warm) to .008 and .012 respectively, Adjusted the timing according to the sticker on my hood, Replaced Crank seal and o-ring.. pressure washed the whole underbelly, discovered a nifty marlin crawler button punched onto my tranny, and I must say.. She is one peppy, happy truck these days
08-22-2011, 02:15 PM
#134
now its just the classy miss with the egr in and at idle "they all do that" says pops. Whatever! I'm just stoked she's happy. Oh the grommet to the valve cover that the pcv goes into is toast.. fortunately.. lexus uses the same grommet. I've got my dad bringing me home one whenever he gets home from work. 
"they all do that" says pops. Whatever! I'm just stoked she's happy. Oh the grommet to the valve cover that the pcv goes into is toast.. fortunately.. lexus uses the same grommet. I've got my dad bringing me home one whenever he gets home from work.
08-29-2011, 04:20 PM
#137
no decals good sir! I did however do my headlight trim and toyota emblem
and got a cat back 2 1/4 with flowmaster quoted at 250 bucks, and 450 with a highflow cat if i dont pass smog at my local muffler shop.
and got a cat back 2 1/4 with flowmaster quoted at 250 bucks, and 450 with a highflow cat if i dont pass smog at my local muffler shop.
